Antimicrobial Stewardship and Financial Outcomes Following Implementation of an Infectious Diseases Pharmacist Team at a Community Hospital

Purpose: Utilizing an antibiotic stewardship program (ASP), antibiotic use can be enhanced by pharmacists. However, no studies evaluate ASP implementation outcomes through incorporation of an infectious diseases (ID) pharmacist team at a community hospital. This evaluation aimed to: (1) determine the net return of the ID pharmacist team implementation through an antibiotic cost-avoidance counterfactual estimate; (2) evaluate usage trends of carbapenems, fluoroquinolones, and total antimicrobial use (AU) which encompassed all antibiotics, antivirals, and antifungals; (3) assess healthcare facility-onset Clostridioides difficile infection (HO-CDI) rates pre- and post-implementation of a 0.6 full-time equivalent (FTE) ID pharmacist team. Methods: Single-site, retrospective, descriptive evaluation which consisted of adult patients (≥18 years) who received antibiotic, antiviral, or antifungal administrations or were diagnosed with HO-CDI during the study periods. The ID pharmacist team was implemented in September 2022. The pre-implementation period data for outcome (1) was collected from January 1, 2018, to December 31, 2020. The pre-implementation period data for outcomes (2) and (3) was collected from January 1, 2019, to December 31, 2020. The post-implementation period data for all outcomes was collected from January 1, 2023, to December 31, 2025. Patient-level data was not included. Descriptive statistics were used for data analysis. Results: The antibiotic cost-avoidance counterfactual estimate yielded an estimated net return of ~$323K for the implementation of the ID pharmacist team (~$639K avoided against ~$316K invested). Total AU decreased by 11.6% (−72.2 days of therapy (DOT)/1000 days present). Carbapenem use decreased by 75.6% (−27.6 DOT/1000 days present) and fluoroquinolone use decreased by 57.9% (−18.3 DOT/1000 days present). The incidence rate of HO-CDI per 1000 patient days decreased by 63% (incidence-rate ratio (IRR) 0.37; 95% CI [0.20-0.70]). Conclusion: Findings display a positive net return for the implementation of the ID pharmacist team based on an antibiotic cost-avoidance counterfactual estimate. There was a decrease in total AU and utilization of high-risk Clostridioides difficile- causing antibiotics. A lower incidence rate of HO-CDI was observed. Results could be associated with antimicrobial stewardship (AMS) efforts correlated with implementation of the ID pharmacist team.